The Game of Go

This post actually has very little to do with programming, but is about a topic that some programmers might find interesting anyway. As the title implies, it is about the game of Go; which is also my favorite board game.

As a quick recap for those who don’t know, Go is an ancient chinese game developed around 4,000 years ago and played mostly by chinese, korean, and japanese people. However there is a growing player base in the US along with strong players in Germany and other areas of Europe. Go is the oldest board game still played in its original form, which is interesting because the rules are still being tweaked in official play. The game is played on a wooden board with 19 horizontal and 19 vertical lines called a goban. Two players place white and black playing pieces called stones on the intersections of the grid in an attempt to surround empty space and/or opponent pieces. Each player is attempting to control more of the board than the other player.

The rules are actually really simple. Players take alternate turns, starting with black, placing stones on the board. Stones of the same color that touch each other are considered a unit and treated as a single stone for the purpose of capture; to capture one you must capture them all. To capture a stone you must surround it with your own stones so that the unit no longer has any empty spaces next to it. Stones cannot be moved after they are placed unless they are captured, in which case they are removed from the board. You cannot place a stone on the board if placing it would result in immediate capture. This means you can’t place a piece on an intersection that has no free space next to it, unless that piece would capture a neighboring piece of the opponent and therefor free up some space. At the end of the game each player counts up the number of empty spaces their stones are surrounding and subtract from that the number of stones of theirs that were captured (Japanese rules anyway… there are variations). Whoever has the most points wins.

Now there’s a few extra parts to this. Since black goes first, black has first choice at placing a piece on the board. This gives black an advantage that is worth a few points. To compensate for this, white is given a ‘komi’ at the beginning of the game, currently often 6.5 points. This means that white starts with 6.5 points automatically for having gone second. The half point is there to prevent ties. There’s also an additional rule that the board cannot repeat itself. Certain configurations will result in what is called ‘ko’. From Sensei’s Library: “[Ko] describes a situation where two alternating single stone captures would repeat the original board position. Without a rule preventing such repetition, the players could repeat those two moves indefinitely, preventing the game from ending. To prevent this, the ko rule was introduced.”

The game is fairly easy to learn. Children as young as 2 can pick up the basic concepts and some strategies for the game. Wikipedia has one of my favorite descriptions about Go as it relates to mathematics: “In combinatorial game theory terms, Go is a zero sum, perfect information, partisan, deterministic strategy game, putting it in the same class as chess, checkers (draughts), and Reversi (Othello); however it differs from these in its game play. Although the rules are simple, the practical strategy is extremely complex.” Quite a bit more complex than chess I would say, while easier to learn. A game like that is something I find intriguing.

While Go is more popular in Asia, there is some support for it in the US as well. The American Go Association has a ranking system, official rulesets, holds tournaments, and tracks clubs where you can go to find players to learn or play the game. A friend of mine hosts a Promote Go website that has club listings in an easier to search form.

There are many websites and books to learn Go. A company called Slate and Shell publishes what is probably the largest set of English books on the topic. You can also play games online for free if you cannot get in contact with any players in your area. A great place to start would be KGS, which has a simple Java client that works on all platforms along with a server that hosts many games for free. There are other programs that use the Internet Go Server (IGS) protocol and can connect to a variety of servers, the most popular of which is pandanet. There are also computer opponents (stay away from them for the most part) along with computer learning games and versions for other platforms such as the xbox 360 and most mobile phones.

I encourage everyone to give the game a try as it can be one of the most mentally rewarding board games you’ll ever experience. If you’re ever interested in picking up a game with me, leave a comment or email me at jearil at gmail dot com.